U.S. Provisional Application No. 61/277,758, filed Sep. 29, 2009, is incorporated herein by reference in its entirety.
Presently, there is an increased demand for corn cobs as a feedstock for cellulosic ethanol, as well as other uses. As a result, there is heightened interest in collecting corn cobs during corn harvest. There is also concern by some that cob collection may reduce soil nutrient content. In this regard, crop residue or stover, e.g., corn stalks, leaves, husks and cobs, are traditionally left on the field after harvest, and break down over time to replenish soil nutrients. If a component of the stover, e.g., cobs is instead collected, nutrient levels could be lowered as a result. To mitigate this concern, some consider it desirable when collecting cobs, to collect mostly just the cobs, that is, with substantially all loose or detached residual elements of the residue, which are lighter than the cobs, mainly, husks and leaves and fragments thereof, returned to the field. Thus, it is sought to have a cob conveying system adapted for operation in connection with a corn harvester, and optionally a cob collection device, which incorporates an ability to separate or remove other lighter crop residue or stover from the cobs, and return the other lighter residue to the field or direct it to another location.
Numerous apparatus have been proposed for use in connection with cob conveying devices, for cleaning or separating other stover and crop residue from the cobs. To illustrate, prior to the early 1960's, the common corn harvesting practice involved picking the ears of corn in the field, removing husks from the ears, and transporting the ears still containing the corn kernels to a corn crib, and later shelling the corn off of the cobs at a stationary sheller. This harvesting procedure has been almost entirely replaced by modern self-propelled combine type harvesters, which separate and collect the corn kernels, and discharge the cobs and other stover onto the field.
Combines which harvest the corn and separate the kernels from the cobs and other stover or residue, then discharge the cobs and other stover onto the field, are now the industry standard. More recently, devices for collecting cobs discharged from combines have been developed. Several of such known devices have variously utilized a towed cart or wagon for receiving and holding the cobs, and a conveying system for conveying the cobs from the combine to the cart or wagon. Some of the cob collection devices also include apparatus for separating the cobs from the lighter other stover or residue downstream or remotely from the combine, mainly using air flow. Reference in this regard, Flamme U.S. Pat. No. 5,941,768, issued Aug. 24, 1999, which discloses a cob collection unit pulled behind a combine to collect on a first conveyor all the residue discharged from the combine, with a separation unit behind the conveyor including a second conveyor, and utilizing a fan to suck the lighter stover from the cobs as they are released from the top of the second conveyor and to blow the stover back onto the field. Redekop et al. U.S. Patent Publication Nos. 20090095662 published Apr. 16, 2009; 20090104952 published Apr. 23, 2009; and 20090124309 published May 14, 2009, disclose a pulled cob collection unit, which utilizes a sequential series of inclined belt conveyors, and blower or suction fans disposed remotely from the combine for directing air through the discharged material as it falls from the upper end of one conveyor onto a lower end of the next conveyor, such that the heavier cobs are to continue to the next conveyor and the lighter stover or residue will be carried away by the air flow, with the cobs being conveyed into a collection tank by a further conveyor or conveyors.
An observed shortcoming of the above referenced known cob conveying and cleaning systems, is a lack of utilization of available air flow discharged from the cleaning system of a harvester, which air flow can be quite voluminous. The known systems also do not use existing residue spreaders in a residue cleaning or separating capacity. At most, when the known cob cleaning systems are utilized, the existing spreader is either not used, or used only for minor chaff distribution and spreading roles. As another shortcoming, the fans of the known residue separating systems are also carried on the trailer, adding additional apparatus, weight, complexity, and power requirements to the trailer.
Thus, what is sought is a cob conveying and cleaning system for use in association with a corn harvester such as a combine, which provides one or more of the capabilities set forth above, namely, effective separating or cleaning of lighter other crop residue from the cobs, utilizing available apparatus and capabilities found on a harvester, namely, air flow from the cleaning system of the harvester, and existing residue spreader devices, while minimizing shortcomings of known devices and systems, namely, increased apparatus, weight, complexity and power demand of a trailer towed by the harvester.